In 1952, a Republican member of the Phoenix City Council, Barry Goldwater, defeated Senate Majority Leader Ernest McFarland. For the next 52 years, until Tom Daschle (D-S.D.) lost in 2004, no party’s Senate leader was defeated. But political polarization has increased leaders’ conspicuousness and vulnerabilities. McConnell, who in 2002 won with 65 percent, won in 2008 with just 53 percent.

Grimes’s cringe-inducing campaign has depended on a migraine-inducing argument: She broadly disagrees with her party’s leader, but it is important that she help perpetuate Harry Reid’s iron-fisted shutdown of the Senate for Obama’s convenience. Her campaign has raised more money than McConnell’s in three consecutive quarters, but money is not magic, which would be needed to make her candidacy coherent.

Although Senate races in many states remain close — McConnell remembers Republicans losing control of the Senate in 1986 by about 25,000 votes in five states — he anticipates a Republican majority in 2015. Then, he says, “a lot of institutional repair” will begin.